Automatic pump control

ABSTRACT

An automatic pump control for oil wells and the like is provided with a pair of pressure sensitive electrical switches which are activated by pressure of fluid within the well. One of the switches is closed at a relatively low pressure and the other switch is closed at a relatively high pressure and these switches are incorporated in a circuit which actuates a pump when the fluid within the well reaches a predetermined high level and deactivates the pump when the fluid within the well reaches a predetermined low level.

O United States Patent 1151 3,679,325 Yost 51 July 25, 1972 54] AUTOMATIC PUMP CONTROL 2,395,007 2/1946 Leupold ..200/83 PA 2,485,074 10/1949 Stevenson. ..417/25 [72] li T52 1 Dnve, Evan 1,913,557 6/1933 Millar ...417/25 3,187,135 6/1965 Slager... 200/83 PA 22 i Sept 1 970 3,318,247 9/1967 Yost ..4l7/44 PP N04 725568 Primary Examiner-William L. Freeh Attorney-Larson, Taylor and Hinds [52] U.S. Cl ..4l7/17, 417/38 511 ..F04b 49/00 [57] ABSTRACT [58] Field of Search ..417/25, 44; 200/83 J, 83 PA, An automatic pump control for oil wells and the like is pro- 200/153 vided with a pair of pressure sensitive electrical switches which are activated by pressure of fluid within the well. One of 56 References Ci the switches is closed at a relatively low pressure and the other switch is closed at a relatively high pressure and these switches UNITED STATES PATENTS are incorporated in a circuit which actuates a pump when the fluid within the well reaches a predetermined high level and 2,240,607 Buck deactivates the p p when the within the we reaches a 3,260,816 7/ 1966 Shad ....200/83 J predetermined low level 2,968,707 1/1961 Martin et al.. ....200/153 3,001,045 9/1961 Rosowicz ..200/83 PA 1 Claim, 3 Drawing Figures qjj I ll 7 f I3 II: V? I: I4

8 i f27 E /2 PATENTEDJUL25 1912 SHEET 2 [IF 2 AUTO INVENTOR ATTORNEYS CLYDE E YOST FIG. 3

AUTOMATIC PUMP comer.

BACKGROUND OF THE INVENTION This invention relates to an automatic pump control which is an improvement on the pump control disclosed and claimed in my prior U.S. Pat. No. 3,3 I 8,247 issued May 9, 1967.

In my prior patent there is a control mechanism for a pump which includes a ball valve which opens when the fluid pressure reaches a predetermined level. When this ball valve opens the exterior fluid activates a switch which starts the pump motor. The pump continues to operate until the fluid within the well reaches a predetermined low level. This system has proved satisfactory but the accuracy has been considerably affected by temperature variations, frictional resistance and due to the fact that the system cannot withstand rough handling. Accordingly, the need arose for a pump control mechanism which provides greater accuracy despite temperature variations and which is capable of withstanding relatively rough treatment.

SUMMARY OF THE INVENTION According to the present invention there is provided a pump control unit which is adapted to be located within a well and which is adapted to control a pump motor through an electrical circuit including a pair of switches activated at predetermined pressure levels and located within the pump control unit. The unit disposed within the well includes a plunger which is moved by fluid pressure acting against a diaphragm. The plunger is mounted for a limited degree of free movement and this free movement is sufficient to close one of the micro switches. Adjustable spring means is provided on the plunger so that further movement of the plunger is controlled by the spring pressure and when the fluid pressure on the diaphragm is sufficient to overcome this spring pressure the plunger will move further to close the second micro switch An electrical circuit including these switches activates a pump motor when both of the switches are closed. The pump draws liquid from the well and continues to operate until both switches are opened. The system is reliable and accurate, free from error due to temperature variations and is sufficiently rugged to withstand rough handling.

An object of the present invention is to provide an automatic pump control for regulating the liquid level in a well which will actuate the pump when the liquid reaches a predetermined high level and will continue to operate the pump until the liquid reaches a predetermined low level. Another object of the present invention is to provide an automatic pump control including a pair of pressure actuated switches which are operated at predetermined pressure levels to control the energization of a pump motor.

Still another object of the present invention is to provide an automatic pump control for a well or the like which is accurate, inexpensive to construct and is capable of withstanding rough handling.

Other objects and many of the attendant advantages of the present will become more fully apparent when taken in connection with the accompanying drawing wherein:

FIG. 1 is an elevational view of the automatic pump control housing,

FIG. 2 is a sectional view through the mid portion of the pump control unit shown in FIG. 1 and FIG. 3 is a circuit diagram of the pump control.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now more specifically to the drawings wherein like numerals indicate like parts throughout the several views there is shown in FIG. I a casing for the elements of the pump control which are to be inserted in the well the casing assembly includes an outer lower casing structure 1 an intermediate section 2 an upper switch housing 3 and a cap assembly 4. A cable 5 extends from the cap assembly 4 through a watertight fitting. As shown in FIG. 2 the lower casing element 1 is secured to mid casing section 2 by means of a collar 6 which is screw threaded into both sections. The casing member 1 is open at the lower end thereof and has apertures in the wall as shown at 7 in FIG. 1. Thus, fluid within the well can enter through the open lower end and fill the entire lower casing 1 and the bore within collar 6.

The central section 2 of the pump control unit has secured therein a tubular collar 7 having reduced end portions 8 and 9 thereon. The upper casing element 3 is secured over the reduced end portion 9 of collar member 7. The inner bore of the collar member 7 is threaded as shown at 10 and a nut member 11 having threads on the exterior periphery thereof engages threads 10. A collet 12 is slidably disposed within a bore in the collar 7 and is urged into the position shown by a spring element 13 which extends between nut 1 l and a flanged end portion 14 on the collet 12. A plunger 15 is slidably disposed within the bores in collet l2 and nut 11 and the plunger has an enlarged head 16 which is disposed within a recessed end portion in collar 7. There is provided a resilient diaphragm 17 which extends across the end of collar 7 and is retained in position by means of a gasket 18 and washer 19.

The upper casing assembly 3 encloses a pair of micro switches S-1 and 8-2 which are fixed within an inner housing 20. Slidably disposed within one end portion of inner housing 20 is a contact block 21 having contacts 22 and 23 mounted thereon for contact with switches S-1 and 8-2 respectively. The contacts 22 and 23 comprise headed screws and are retained on member 21 by means of nuts 24 and 25 respectively. Contact 22 is slidable within a bore in block 21 and is retained in the position shown by means of a spring 26 so that as slidable contact block 21 moves inwardly within housing member 20 and contact 22 contacts switch S-l further inward pressure will compress spring 26. Contact 23 is, on the other hand, screw threaded within block 21 so that the position thereof is fixed when the nut 25 is tightened.

It can be seen that the plunger 15 has a limited degree of free upward movement before the end face of head 16 contacts the end face of collet 12. This upward movement of plunger 15 is sufficient to cause the block 21 to move upwardly to the point where contact 22 closes switch 8-1. In order for the plunger 15 to move upwardly to a greater degree the pressure of spring 13 acting against collet 12 must be overcome to permit the plunger 15 to move upwardly to a point where the inner face of enlarged head 16 engages shoulder 27 of collar element 7 When the plunger moves upwardly to this extent contact 23 closes switch 5-2, the switch S-1 remaining closed with spring element 26 compressing with upward movement of the plunger 15.

Thus, with the pump control being disposed in a well it can be seen that the liquid level rises within the lower section I to contact diaphragm 17. When this liquid level reaches a predetermined point such that the pressure against diaphragm is 'sufiicient to raise the plunger 15 until the head 16 contacts the end of collet l2, switch S-l closes. As the liquid level continues to rise the pressure against diaphragm 17 increases until such time as the pressure is sufficient to overcome the force of spring 13 to move both the plunger and collet 12 upwardly until the head 16 of plunger 15 contacts the shoulder 27. At this point 8-2 is also closed. It can be seen that the amount of spring pressure against collect 12 may be adjusted by moving the nut l 1 inwardly or outwardly within collar 7.

Referring to FIG. 3 the circuit for the pump motor is shown. The switches 5-1 and 8-2 are disposed within the control unit shown in FIGS. 1 and 2 within the well and these switches are electrically connected via cable 5 with the electrical circuit to actuate the pump motor and these circuit elements may be located at a point remote from the switches S-1 and 8-2.

The conductors 31 and 32 connect the power supply 33 with the motor which serves to operate the pump to lower the fluid level within the well. The power supply is connected with the motor through a relay switch 34 controlled by a coil 35. The relay coil 35 is controlled by a circuit including a power source 36, switch 37 and relay 38. The switch 37 is a three position switch and it can be seen that when the switch is in the on position the relay coil 35 is energized from power source 36 to close switch 34 thereby energizing the pump motor. When the switch 37 is in the automatic position the energization of coil 35 is controlled by switches 84 and 8-2. When switch 8-1 is closed it can be seen that there is no complete circuit through the coil 39 of relay 38 but upon the subsequent closing of switch S-2 coil 39 is energized through conductors 40, 41, switch S-l, switch S-2 and conductor 42. When coil 39 is energized switches 43 and 44 are closed. Switch 44 completes the circuit for relay coil 35 through conductors 45, coil 35, conductor 46, switch 37, conductor 47, switch 44 and conductor 48. Switch 43 maintains the circuit through coil 39 complete after switch S-2 opens and coil 39 will continue to be energized until switch S-l opens.

It can thus be seen that by virtue of the circuit shown the pump motor will be energized when both switches S-1 and 5-2 are closed. The pump motor will continue to operate and reduce the liquid level within the well until both switches S-1 and 8-2 are opened. In this manner the pump control shown will cause the pump to be energized when the liquid level reaches a predetermined high point and will operate the pump continuously until the liquid level reaches a predetermined low level. The level at which the switch S4 is actuated can be readily set by adjusting the compression of the spring 13 by rotating nut 11. The point at which the switch 8-1 is operated can be set by adjusting the location of the pump control unit within the well. Normally, the pressure created by 18 inches of fluid is sufficient to cause the plunger to move upwardly in its free movement to close switch 8-1.

It can be seen that there is provided a pump control mechanism which is of simple construction, may be readily adjusted and yet has relatively few moving part and can withstand rough handling. The accuracy of the unit is not appreciably affected by temperature variations or by variations in frictional resistance.

Obviously many variations and modifications of the present invention are possible in light of the foregoing teachings. What is claimed is new and is desired to be securred by Letters Patent is:

1. An automatic pressure control unit for controlling the connection of a power supply and pump motor in response to pressure conditions comprising a casing, said casing having an open lower end, a diaphragm disposed within the casing, a plunger slidable within the casing having one end disposed adjacent the diaphragm, the plunger having a limited degree of free movement, spring means resisting further movement of said plunger, a pair of switches mounted within the casing adjacent the other end of said plunger, a pair of contacts for closing the switches in response to movement of the plunger, a slidable block supporting said pair of contacts, one of said contacts being mounted in said block for slidable movement and being spring urged to one end position, the other of said contacts being mounted in fixed position on said block whereby exterior fluid pressure acts against the diaphragm and at a predetermined low level moves the plunger the free movement thereof to slide the block vertically and move said one contact to close one of said switches and at a predetermined high level of exterior fluid the pressure is sufficient to overcome the spring pressure on the plunger and move the plunger further to cause said other contact to close the other of said switches, and circuit means including said switches for closing a control circuit with both of said switches closed and for opening the control circuit with both of said switches open, said circuit means including a pair of relays, one of said relays including a second pair of switches, one of said second pair of switches closing the circuit to the other of said relays, the other of said pair of switches holding said one relay closed, and the other of said relays including means for connecting said power supply and said pump motor.

II i 

1. An automatic pressure control unit for controlling the connection of a power supply and pump motor in response to pressure conditions comprising a casing, said casing having an open lower end, a diaphragm disposed wIthin the casing, a plunger slidable within the casing having one end disposed adjacent the diaphragm, the plunger having a limited degree of free movement, spring means resisting further movement of said plunger, a pair of switches mounted within the casing adjacent the other end of said plunger, a pair of contacts for closing the switches in response to movement of the plunger, a slidable block supporting said pair of contacts, one of said contacts being mounted in said block for slidable movement and being spring urged to one end position, the other of said contacts being mounted in fixed position on said block whereby exterior fluid pressure acts against the diaphragm and at a predetermined low level moves the plunger the free movement thereof to slide the block vertically and move said one contact to close one of said switches and at a predetermined high level of exterior fluid the pressure is sufficient to overcome the spring pressure on the plunger and move the plunger further to cause said other contact to close the other of said switches, and circuit means including said switches for closing a control circuit with both of said switches closed and for opening the control circuit with both of said switches open, said circuit means including a pair of relays, one of said relays including a second pair of switches, one of said second pair of switches closing the circuit to the other of said relays, the other of said pair of switches holding said one relay closed, and the other of said relays including means for connecting said power supply and said pump motor. 